The CO preferential oxidation (PrOx) is one of the critical steps in hydrogen production and purification for Polymer Electrolyte Membrane Fuel Cell (PEMFC). This reaction was investigated in the presence of excess hydrogen over Cu/CeO2, Pt/CeO2 and Cu-Pt/CeO2 catalysts. The ceria supports was prepared via precipitation method and Cu-Pt/CeO2 catalyst was synthesized by sequential impregnation on ceria. The catalysts were characterized by XRD. Comparison of ceria supported copper and platinum showed that copper catalysts activity was higher than platinum in PrOx process. Effect of platinum addition on ceria supported copper was investigated and results showed that Pt promoter have positive effect on CO conversion in low temperature (